Is it possible to extend the pervasive trial licence by another 30 days?

Technically, yes. You need a different evaluation key and just add it
to the engine, but you'll need to talk to someone who has a key that
they will send you.

Just contact your Pervasive Territory Sales Manager or your
application vendor and tell them why you need it (and which product
and how many seats) and they should be able to get you some additional
time.

JohnR